Piston-packing.



Patented 1an. l, |90l.

T. G. SAXTON.

PISTON PACKING.

2 sheefswshet 2.

I Witwe/moo THOMAS GUNNI SAXTON, OF LEXINGTON, KENTUCKY, ASSIGNOR TO J.ROGERS BARR, OF SAME PLACE.

SPECIFICATION forming part of Letters Patent No. 665,271, dated. January 1, 1901.

Application fled February 2t, 1900. Serial No. 6,626. (No model.)

I do hereby declare the following to be a full,

clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

This invention relates to pistons; and it consists, substantially, insuch features of improvement as will hereinafter be more par` ticularlydescribed.

The invention has reference more particularly to that class or type ofpiston with which is combined a metallic packing for maintaining thepiston Huid-tight Within the working cylinder of a steam or othermotive-power engine. have been heretofore devised; but in a large numberof instances the same have not fully met the requirements, in thatleakage very soon takes place, due to imperfect expansion of the packingring or rings or else to the unevenness of Wear either of the piston orof the 'said packing. Moreover, in some cases heretofore considerablediiiiculty has been experienced in fitting the piston and its packingwithin the cylinder, as well as in removing the same from the cylinderfor the purposes of adjustment or repair.

The object of the present invention is to overcome the inconveniencesand difficulties pointed out and to provide a combined piston andmetallic packing therefor which are capable of easy and uniformadjustment and which coperate in such manner as to prevent leakage ofthe motive-power fluid, as well as securing even wear between the pistonand its packing and between the latter and the cylinder.

The above and additional objects are attained by means substantiallysuch as are illustrated in the accompanying drawings, wherein.

Figure l is a longitudinal sectional View of a combined piston andmetallic packing therefor constructed and arranged in accordance with myinvention, and Fig. 2 isatransverse sectional view illustrating furtherfeatures of Many forms of pistons of this typev the invention sometimesadopted. Fig. 3 is an enlarged view in perspective of one of the mainparts or elements of my improved structure, and Fig. 4. is a similarView of another part cooperating therewith. Figs. 5 and 6 are enlargedviews in detail of certain parts more fully understood hereinafter.Figs. '7 and 8 are enlarged views in detail representing theconstruction or form of packing-rings employed. Figs. 9 and lO aresimilar views to Figs. 1 and 2 and representinga modification of theconstruction shown by said latter figures.

In carrying my invention into effect I construct the piston in part of adisk or plate l of suitable thickness,the same havinga diameter somewhatless than the inner diameter of the cylinder2,in which the piston works.Projecting from said disk on one side is a centrallydisposed hub 3, thesame being'provided with a central longitudinal opening -l for thepassage of the piston-rod 5, which opening registers with a similaropening (not shown) in the disk, also for the passage of the said rod 5.As shown in Fig. l, the end of the pistonrod projects beyond the end ofthe hub, and the same is screw-threaded at 6 for the reception of thenut 7, which screws onto the end of the rod and is tightened up againsta follower plate or disk S, which latter is slipped upon the rod andabuts the end of the hub 3 and in all respects corresponds to the disk labove referred to. The diameters of the disks l and 8 being greater thanthat of the hub 3, a circumferential recess of considerable depth isthus formed between the said disks and hub, and in order to complete myimproved structure or device I employ a suitable metallic packing ofpeculiar construction, one which is thoroughly effective in preservingthe piston steam or Iiuid tight within the cylinder, besides renderingthe wear of the parts considerably less and uniform. Thus, as shown inFig. l, the numeral 9 designates a shell which incloses and closely fitsthe hub 3, the said shell being formed at one end with a liange l0,abutting the inner surface of disk or plate 1, and the said flange beingof a depth equaling the diameter of the said disk, so as to be even orflush therewith at the circumference. The length of the said shell is alit- IOC tle less than the length of the said hub, and secured to theother end of the shell by means of suitable screws 11 is afollower-plate 12, which fits upon the hub and closely abuts the innersurface of the outer or main followerplate 8 of the piston. In additionto being held in place by means of the nut 7, the said mainfollower-plate S is further secured by means of screws 13 passingthrough the same and entering the end of the hub, as shown. Thesescrews, however, can in some instances be dispensed with; but I preferto use the same as a means of security. 'lhe edge or circumference ofthe said plate 12 is flush or even with the edge of the said plate 8,and from the construction shown and described the strength and compactness of the structure are apparent.

Surrounding the shell 9 and fitting closely between the flange 10 andfollower-plate 12 is a longitudinally-split ring 15, (see Fig. 2,) whileinclosing and closely fitting the said ring is a double conoidal splitring 16, (shown enlarged in Fig. 7,) the longitudinal split thereinbeing designated at 17. The said double conoidal ring 16 is providedwith a centrally disposed circumferential fiange 18 for a purpose to bedescribed, and, similarly as with the ring 15, the same is snuglyconfined between the said fiange 10 and follower-plate 12. Fittingaround said ring 16 and held apart by means of the fiange 18 thereon aretwo outer or band rings 19, each being split at 19 and formed with anextension 20, overlapping the edge or circumference of the disk 1 andfiange 10 and follower plates 8 and 12, respectively. The outer surface21 of said rings as thus constructed furnishes increased bearing-surfacefor said rings, and by means of the overlapping portions or extensions2O the piston proper is prevented from coming into contact with thecylinder. Hence no part of said piston proper is subjected to wear, andthe same does not require to be renewed, as is the case in many formerconstructions. The inner surfaces of the rings 19 are beveled at 22 tocorrespond with the double conoidal surface of the ring 16,and in Virtueof this construction it is evident that when the said rings 15 and 16are expanded within the cylinder the double inclined faces lof thelatter ring will move against the said beveled inner surfaces of therings 19 in such manner as to force the surfaces 21 of said rings 19into close contact with the cylinder, and at the same time theabuttingfaces a d of the rings 19 will be forced into closer contactwith the inner surfaces of the flange lO and follower-plate 12,respectively. In this way any wear that takes place at the said abuttingfaces a a is compensated for and largely overcome, since any pressureexerted by the double conoidal ring on the inner beveled surfaces of therings 19 is equally distributed both on said abutting faces and theouter or bearing surface 21.

Any suitable means maybe employed for automatically expanding theseveral abovenamed metal packing-rings, so as to keep the pistonfluid-tight within the cylinder,y as well as to compensate for any wearthat naturally takes place either between the rings and cylinder orbetween the rings themselves. Preferably, however, I employ aspring-actuated wedge-shaped plug 30, (see Fig. 5,) the same working ina screw-threaded nipple 31, fitting at one end in a threaded opening 32in the shell 9. Screwing upon the inwardly-projecting end of said nippleis an elongated neck 33, which also serves as a box for holding thespring 34, which acts upon the said plug 30, and the upper end of saidbox-nut is exteriorly threaded and tapered at to receive a jam-nut 35.As shown at Fig. 6, the tapered portion of the said elongated or box nut33 is also split longitudinally at 36, and it is evident that byscrewing the jam-nut 35 tightlyinto place the different adjustments oft-he plug 30 can be maintained after once having been effected throughthe medium of said nut 33. The tapered or wedge-shaped end of the plug30 enters the split 37 in the ring 15, and. it is evident how the partsoperate without further specific mention on this point.

Inasmuch as the tendency of the rings to expand becomes less as thedistance from the splits therein increases circum ferentially, there isa tendency to bind more on one side than the other and the piston properat times gets out of center with the cylinder. To overcome this and toproperly center the piston proper at all times, I employsuitable devicesin the form of blunt spring-actuated plugs 40, Fig. 2, which bear uponthe inner surface of ring 15 in such manner as to impart to such ring atendency to expand equally at all points, the said plugs being soarranged radially to the piston and relatively to the expanding-plug 30as to effect this result. Ofcourse the same effect is produced on theouter rings, with the effect already described. These said plugs -LLOare constructed, secured in place, and actuated substantially in thesamemanner as the plug 30, excepting that the end of the latter is taperedor wedgeshaped. Hence no further specific description of said plugs 40is thought t-o be necessary herein. From the construction andarrangement described with reference to said plug 30 and the plugs 40,together with their adjusting devices, it is evident that unless specialprovision was made therefor the hub 3 could not enter the shell ashereinbefore set out. Therefore at points of said hub corresponding tothe positions of said plug devices I form longitudinal slots or groovesof proper length and depth to snugly receive said devices when the saidhub 3 and shell 9 are properly fitted together.

At Figs. 9 and 10 I have shown a modification of myinvention, theseveral parts being identically the same in all respects as before,

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with the exception of a slight alteration in the hub and the shellfitting upon the same. Thus in these figures (9 and l0) the said hub ishollow and closed at one end by the disk l, and arranged about the samecircumferentially are a series of ports 61 for the passage of steam orother motive fluid. Said ports register and communicate with similarports 62, formed in the circumference of the shell 9, and thus it willbe seen that the expansion of the several rings is effected by theexpansive power of the fluid itself, which enters the open end of thepiston and passes through said ports in an obvious manner. In this formof my improved piston the pistonrod 5 is secured directly to the disk l,while an opposite opening 65 is provided for the entrance of the fluidto the said ports.

While I have herein shown and described certain preferred details ofconstruction and arrangement of parts, it is to be understood that I donot limit myself strictly thereto in practice.

Having thus fully described my invention, what I claim as new, anddesire to secure by Letters Patent of the United States, is-

l. A piston having a circu mferential recess, and comprising a straightsplit ring located in said recess, a double conoidal split ringinclosing said ring and formed with acentrallydisposed circumferentialflange, outer split rings iitting the conoidal surfaces of saidsecond-named ring on opposite sides of said flange, and meansforautomatically expanding said rings, substantially as described.

2. A piston havinga circumferential recess, and comprisinga straightsplit ring located in said recess, a double conoidal split ringinclosing said ring, outer split rings constructed to lit the conoidalportions of said secondnamed ring, each of said outer rings beingextended to overlap the end disks of the pistou at the circumference,and means for automatically expanding said rings, substantially as shownand described.

3. A piston havinga circumferential recess, and comprising a straightsplit ring located in said recess, a double conoidal split ringinclosing said ring, outer split rings constructed to fit the conoidalportions of said secondnamed ring, and means for expanding said rings,the same comprising a spring-actuated wedgeor bolt entering the split ofthe inner ring, substantially as described.

4. A piston comprising end disks or plates, a concentric hub, a shellsurrounding the hub and having end flanges abutting said end disks orplates, an inner split ring located between said i'langes, a doubleconoidal split ring inclosing said inner ring, outer rings extendingbeyond the circumference both of said disks and flanges, and means forexpanding the rings, substantially as described.

5. A pistou comprising a centrally-disposed hub having longitudinalgrooves therein, a shell fitting upon said hub, expansible metallicpacking-rings inclosing the shell, and an expanding device for saidrings, the same comprising a spring-actuated bolt or wedge supported bythe shell and entering a groove in the hub, substantially as shown andin the manner described.

6. A piston comprising a hub having a series of recesses thereinextending longitudinally thereof and provided with end disks or plates,one of which is removable, a shell fitting over said hub havingapertures therein coincident with said recesses, outwardlyspring-pressedplugs or plungers working in sleeves which extend from the shell intothe recesses of the hub, for expanding the packing-rings which surroundthe shell, together with suitable packing-rings surrounding the shell insuch manner as to be expanded outwardly by said outwardly-spring-pressedplugs or plungers, substantially as described.

7. In a piston, the combination with an expansible split ring, of one ormore split metallic packing-rings surrounding said expansible ring, anda spring actuated bolt or wedge engaging the divided ends of saidexpansible ring for expanding the latter and thereby expanding the saidpacking-rings, and radially-disposed springpressed bolts bearingoutwardly upon the inner surface of said expansible ring, substantiallyas described.

In testimony whereof I affix my signature in presence ol' two witnesses.

THOMAS GUNNI SAXTON.

Witnesses:

W. O. BULLocx, Jr., T. D. MURRAY.

